This fixes the compiler complaining about the __has_include_next.

diff --git a/clang/lib/Headers/unwind.h b/clang/lib/Headers/unwind.h
index 6e069798f..3a24920d1 100644
--- a/clang/lib/Headers/unwind.h
+++ b/clang/lib/Headers/unwind.h
@@ -9,9 +9,6 @@
 
 /* See "Data Definitions for libgcc_s" in the Linux Standard Base.*/
 
-#ifndef __CLANG_UNWIND_H
-#define __CLANG_UNWIND_H
-
 #if defined(__APPLE__) && __has_include_next(<unwind.h>)
 /* Darwin (from 11.x on) provide an unwind.h. If that's available,
  * use it. libunwind wraps some of its definitions in #ifdef _GNU_SOURCE,
@@ -39,6 +36,9 @@
 # endif
 #else
 
+#ifndef __CLANG_UNWIND_H
+#define __CLANG_UNWIND_H
+
 #include <stdint.h>
 
 #ifdef __cplusplus
@@ -326,6 +326,7 @@ _Unwind_Ptr _Unwind_GetTextRelBase(struct _Unwind_Context *);
 }
 #endif
 
+#endif /* __CLANG_UNWIND_H */
+
 #endif
 
-#endif /* __CLANG_UNWIND_H */
-- 
2.35.1

